Method of producing metal-polymer compositions

ABSTRACT

The present invention relates to method of producing metalpolymer compositions. The method of the invention is characterized in that a polymer medium which contains a metal component in the form of ferromagnetic particles or a mixture thereof with nonferromagnetic metal particles is affected by a travelling rotating electromagnetic field. From the metal-polymer compositions thus produced various articles can be manufactured, featuring high mechanical characteristics.

United States Patent Logvinenko METHOD OF PRODUCING METAL- POLYMER COMPOSITIONS [72] Inventor: Dmitry Danilovich Logvinenko, ulitsa Kalinina, 5, kv. 5, Poltava, U.S.S.R.

[22] Filed: Aug 6, 1970 [211 App]. No.: 61,864

[52] US. Cl ..260/41 B, 241/1, 260/37 M, 264/24 [5 1] Int. Ch ..C08f 45/04, C08g 51/04 [58] Field of Search....24l/l, 5; 1264/22, 24, DIG. 58; 252/6254; 260/41 B 9/1962 Baerman ..264/22 51 Sept. 12, 1972 1/1963 Schornstheimer ..264/22 2/1971 Cochardt ..264/24 Primary Examiner-Lewis T. Jacobs Assistant Examiner-P. R. Michl Att0rney-Waters, Roditi, Schwartz & Nissen [5 7] ABSTRACT The present invention relates to method of producing metal-polymer compositions.

The method of the invention is characterized in that a polymer medium which contains a metal component in the form of ferromagnetic particles or a mixture thereof with non-ferromagnetic metal particles is affected by a travelling rotating electromagnetic field From the metal-polymer compositions thus produced various articles can be manufactured, featuring high mechanical characteristics.

15 Claims, No Drawings NETHOD OF PRODUCING METAL-POLYMER COMPOSITIONS The present invention relates to methods of producing metal-polymer compositions based upon synthetic polymers with finely dispersed metal particles spread thereamong.

' The invention has particular reference to methods of obtaining metal-polymer compositions based upon polyamids, polytetrafluoro-ethylene, epoxy resins, or synthetic rubber by introducing powdered chromiumnickel alloyed steels, cast irons, various metal alloys, metal oxides and pure metals thereinto.

There are known at present some methods of obtaining metal-polymer compositions by way of mechanicallyintermixing an dispersing metal particles in a polymer medium effected in ball or colloid mills and mixers (cf. USSR Authors Certificate No. 136,556). However, such a method fails to provide an adequate distribution of metal particles in the polymer medium even when being mixed for a lengthy period of time; besides, this method in incapable of providing metalpolymer compositions containing metal particles as small as tenths and hundredths of a micron.v

Some other methods were proposed, whereby highly dispersed metal particles are shaped in the; polymer medium by thev method of electrolysis. According to said-method a metal-polymer is obtainable in a doublelayer electrolysis bath by dispositing colloidal metal upon a rotating cathode. The method is described in USSR Authors Certificate No. 209,731.

A disadvantage inherent in the above method resides in failure to obtain metal-polymer compositions based upon such metals as aluminum, magnesium, calcium,

potassium, as well as upon various alloys, steels, and

cast irons.

One more method has been proposed, wherein a metal-polymer composition has resulted from a thermal reduction in a vacuum of organic compounds adequately spread in the polymer medium (cf. Transactions of the USSR Academy of Sciences, Vol. 167, No. l).

A disadvantage of the above method lies with the polymer being thermally decomposed and failure to obtain compositions based upon metal alloys.

A common disadvantage inherent in all the abovediscussed methods is the involving of complicated and highly expensive equipment and apparatus.

It is an object of the present invention to provide a method of obtaining metal-polymer compositions that would involve a relatively simple but efficient equipment and apparatus and would be capable of obtaining uniformly spread dispersed particles of metals or alloys in the polymer medium, as well as of dispersing said metal or allow particles immediately in the polymer medium.

. Said object is accomplished due to the provision of a method which, according to the present invention, consists in that the polymer medium containing a metal component in the form of ferromagnetic particles, is affected by a travelling rotating electromagnetic field which captures ferromagnetic particles of the metal component and imparts intense compound motion and magnetostrictive oscillation thereto.

At the same time the polymer component of the composition is exposed to the effect of a travelling electromagnetic field and acoustical waves, this being due metal-polymer to the fact that each of the ferromagnetic particles is in effect a source of such vibrations or waves. It is under the effect of the aforedescribed factors that the ferromagnetic particles are intensely disintegrated from 0.15-15 mm down to 10" 10' cm.

It is expedient that the value of the magnetic induction of a travelling rotating electromagnetic field in the polymer medium that contains said metal component, be at least 0.1 tesla.

Used as ferromagnetic particles are particles of pure ferromagnetic metals or alloys thereof such as iron, nickel, cobalt, steel, cast iron, and the like.

According to one of the embodiments of the present invention the essence thereof may consist in that a travelling rotating electromagnetic field affects the polymer medium containing a metal component which is in effect a mixture of ferromagnetic and non-ferromagnetic metal particles. In this case the non-ferromagnetic metal particles are liable to disperse to those of colloidal size andjto equally spread in the polymer medium with thehelp of ferromagnetic particles that serve as stirring and, disintegrating bodies.

It is also recommended that the ferromagnetic particles serving as stirring and disintegrating bodies, be coated with a protective polymeric film, this being particularly important for those cases where it is necessary to obtain metal-polymer compositions containing nonferromagnetic metal component and free from ferromagnetic inclusions.

It is likewise desirable that said ferromagnetic particles be coated with polytetrafluoro-ethylene protective film.

In case of the use of a mixture of ferromagnetic and non-ferromagnetic particles, the former particles may be made a unequiaxed bodies and be expediently imparted cylindrical shape, this contributing to a more effective spread thereof.

When carrying the method of the invention into effect, said polymer medium can be in liquid or powdered state.

Exemplary polymer media employed for obtaining compositions are polytetrafluoroethylene, polyamid, epoxy resin, phenol-formaldehyde resin.

The herein disclosed method features a number of advantages over the hitherto known ones. It enables the obtaining of metal-polymer compositions based upon synthetic rubber, epoxy resins, polytetrafluord ethylene and some other polymers with adding colloidal and powdered metal, e.g., iron, aluminum, grey cast iron, copper, lead, chromium-nickel alloys, and the like, as well as a system based upon various polymers and metal oxides. The application of the present method considerably simplifies the production technique of metal-polymer materials and involves no complicated and expensive equipment and apparatus. Besides, the process of dispersion proceeds continuously and is readily liable to be fully automated.

Furthermore, the proposed method makes it possible to disintegrate within a relatively short period of time and immediately in polymeric substances, the necessary amount of metal down to particles possessing colloidal size (viz. 0.1 to 0.001 mk). Formation of such particles immediately within the polymer medium is conducive to a substantial improvement in a number of the properties of metal-polymer materials, as well as to the development of new such materials due to forrnation of irreversible adsorption linkages between the macromolecules of polymers and colloidal particles of metals.

Materials obtained on the base of metal-polymer compositions having passed electromagnetic treatment, need no epuration from alien inclusions adversely affecting the quality thereof.

The method enables the particles of powderlike metal fillers to be adequately and quickly spread in the polymer medium at a mixing rate SOD-1,500 times as high as compared to the early methods.

A device for carrying the method of the invention into effect is very simple in construction being essentially a vessel or receptacle made from nonmagnetic, nonconductive material such as nucerite and provided with inlet and outlet pipes for primary components to charge and discharge, respectively. The container is placed in a generator of electromagnetic rotating field.

Then a necessary amount of unequiaxed ferromagnetic particles are charged into the container, such as nickel, steel, cobalt, cast-iron particles, as well as a and the molecules of polymer resulting in appearing new properties of a metal -polymer compositions.

Should necessity arise of dispersing non-magnetic metal particles to the particles of colloidal size, the

container of the apparatus is charged with the particles of a ferromagnetic metal along with the non-magnetic particles sizing 0.5-5 mm each, the ratio between the amounts of the ferromagnetic and non-magnetic particles ranging from 1:1 to 1:100. In this case both ferromagnetic and non-magnetic metal particles are dispergated to colloidal size, the dispergating of non- TABLE 1 Ace. to the By conventional present method mechanical methods Weight percentage Mixing Mixing Mixing Mixing Experiment of compotime, degree, time, degree, No. Components being intermixed nents see. percent hrs. percent Polycarbonate 99 1 "{Tittmiugl dioxide 99 g; 5

Polyear onate 2 "{Powdered aluminium 0. 2 i 12 5 5 6 Polytetral'l uoro-eth ylene 87 3 Powdered nickel 10 15 09.1 8 96.4

Molybdenum disulphide 3 Polytetrafluoro-ethylene 87 4 Powdered nickel 1O 15 99.1 8 96.2

Grpphiteti 03 P0 yami 5 "{PowderedlnickflI .id.i a M1) 15 5 5 Novolac p ieno orma e 1y e resin 6 "{Powdered aluminium N 10 60 5 powder or suspension or else a solution of a polymer, or 40 The thus-obtained compositions are then a liquid polymer, that is, polymer medium in which ferromagnetic component is to be dispergated and equally spread. The amount of the metal component to be charged depends on the desired properties of the final product to obtain.

Under the effect of the rotating electromagnetic field produced by the generator the metal ferromagnetic particles perform compound intense motion, i.e., rotation about their least axis at a speed nearly equal to rotation speed of the field, translational and oscillating motions, as well as magnetostrictive oscillations (magnetic induction efiective within the dispergation zone being at least 0.1 tesla).

At the same time the non-ferromagnetic (polymeric) component of the composition is subjected to the effect of a travelling electromagnetic field and acoustical waves, this being due to the fact that each of the ferromagnetic particles is in fact a point-source radiator of such waves or vibrations.

Thus, all the components are caused to intensely moved and intermixed.

Under the effect of all the afore-listed factors the ferromagnetic metal particles are vigorously superficially disintegrated from 0.15-15 mm down to 10" l 0- cm.

The surface of the newly formed metal particles possesses high activity, whereby there arise irreversible adsorption linkages between the metal colloidal particles reprocessed into finished products by conventional techniques.

The examples cited hereinbelow are to further illustrate the specific and preferred embodiments of the present invention. However, it should be understood that the scope of the invention is by no means restricted to said examples.

Given below are some examples of obtaining metalpolymer compositions based upon polytetrafluoroethylene, epoxide resin, synthetic rubber, polyamid, and some results of varying the mechanical properties of materials made from said compositions.

All the compositions disclosed hereinbelow have been obtained in an apparatus featuring the following technical characteristics: the value of magnetic induction effective within the working zone of the apparatus 0.13 tesla; rotational speed of the electromagnetic field 3000 rpm.

EXAMPLE 1 a. A mixture comprising g of polytetrafluoroethylene and 300 g of steel (weight percentage composition: C l; Cr 18; Ni 13 9; Ti 1; Fe 71) in the form of cylindrical-shaped particles 6-7 mm long and 1.2 mm in diameter, has been exposed to rotating electromagnetic field in the presence of ethyl alcohol, the process of dispersing said mixture lasting 20 min.

b. Another mixture has been obtained due to dispergating the particles of said steel component in an amount of 300 g in ethyl alcohol within min under the eflect of rotating electromagnetic field, whereupon 100 g of polytetrafluoro-ethylene have been added, and 5 the resultant mixture has been treated within 5 min.

Thereupon, the solid phase (both in variants a and b) has been isolated from the alcohol fraction by filtering and then dried at l00120C during 24 hrs. The dried mixture has been pressed and caked separately for the variants a and b at 360-390C and a compression moulding pressure of 300-350 kg/cm the speed of the patrix being 6-7 cm/min and injection boost time, 2-3 min. Caking occured in an oven and without compression mould. Then the specimens have been heat treated at 390C during 4 hrs and then oven-cooled down to 200 C during 1.5 to 2 hrs, whereupon the specimens have been taken from the oven to be air-dried. Two final products have been obtained, viz., polytetrafluoro-ethylene with 0.05 percent content of colloidal steel (variant 0) and that with 0.45 percent content of colloidal steel (variant 1:).

Physico-mechanical and electrical characteristics and properties of the materials obtained are present in 5 Table 2below. v i

. I 7 TABLE 2 Physico-mechanical and pure popolytetrapolytetraelectrical lytetrafiuorofluorocharacteristics fluoro- -ethylene -ethylene L -ethylene with 0.05 with 0.45 e pct steel pct steel Tensile strength, kg/cm 233 252 279 Ultimate elongation, v,

percent 275 287 293 Brinell hardness, ltglcm' 5.05 5.59 Surface resistivity, ohm 5.3.10" 9.10" 4.3.19! Volume resistivity, chimera 4 2.4.10" 2.3.10 2.3.10" v Dielectric power factor at 10' cps 0.0005 0.0005 0.0007 40 Permittivity at 10 cps 2.0 2.0 2.1

As it can be seen from the above table the introduction of stainless colloidal steel into the powdered polytetrafluoroethylene brings about an efiective increase in the mechanical characteristics thereof.

EXAMPLE 2 t A mixture composed of 500 g of epoxy resin with percentage content of epoxy groups equal to 18,35 g of powdered aluminum (particles 0.5-2.5 mm in diameter) and ferromagnetic particles (steel), is heated up to 80C by placing in rotating electromagnetic field.

The process of dispersing the metal particles takes 5 min.

The product obtained is allowed to settle for 24 hrs at 20C. The resultant composition contains 0.02 percent of colloidal aluminum, determined by a chemical analysis.

In the obtained composition there are added 15 weight percent of polyethylene-polyamine, the mixture 0 is dispensed to moulds and subjected to polymerization at 20C. The mechanical properties of the final product is indicated in Table 3 below.

TABLE 3 6 EXAMPLE 3 as a result of polymerization of the metal-polymer composition, are present in Table 4 below.

TABLE 4 l. Modulus of elasticity, kg/cm' 0.033.10' 2. Compression strength, kg/cm' 986 3. Unit strainat static bending 10.8.10"

EXAMPLE} A mixture of 50 g of liquid rubber, 10 g of epoxy resin, 1.5 g of triethanolamine and 200 g of stainless steel particles the same as in Example 1 (6-7 mm long and 1.2 mm in diameter), is heated up to 60C, whereupon is placed in rotating electromagnetic field.

Dispersing of steel and intermixing of components in electromagnetic field takes 5 minutes.

The resultant product is dispensed to moulds and kept in a thermostat within 30 hrs at a temperature of C-5C. After the polymerization process has been over, standard specimens are to be made to test for the mechanical properties thereof. The final product contains 0.02 percent of colloidal steel.

Mechanical characteristics of the materials containing 0.02 percent of colloidal steel and free from it are stated in Table 5 below.

TABLE 5 Mechanical Specimen free Specimen containcharacteristics from colloidal ing 0.02 percent steel of colloidal steel 1. Ultimate elongation,

percent 445 810 2. Permanent elongation,

percent 4 18 3. Tensile strength, kg/cm 23.2 21.0

EXAMPLE 5 A mixture composed of g of polytetrafluoroethylene and 100 g of steel the same as stated for Example 1 above in the form of cylindrical-shaped particles 6-7 mm long and 1.2 mm in diameter, is placed in rotating electromagnetic field, wherein the metal component of the mixture is subjected to dispersing down to colloidal size within 45 minutes. Then specimens are made from the obtained product by resorting to the technique described above with reference to Example 1.

As a result a metal-polymer composition is obtained based upon polytetrafluoro-ethylene with a 2.2 percent content of colloidal steel, the physico-mechanical properties of said material being given in Table 6 below.

TABLE 6 Tensile strength, kg/cm 95 Ultimate elongation, percent 37 Brinell hardness, kglmm' 5.82

EXAMPLE 6 A mixture comprising 100 g of polytetrafiuoroethylene and 100 g of nickel particles -7 mm long and die. 1 mm each, is placed in rotating electromagnetic field, the experiment having been repeated a few times at different duration of exposition to electromagnetic field. The product obtained undergoes pressing and heat treatment as per the technique described with relation to Example 1. Data on the influence of dispersing conditions upon the physico-mechanical properties of the compositions of polytetrafluoroethylene with colloidal nickel are quoted in table 7 below.

TABLE 7 Physico-mechanical properties Duration of treatment in of polytetrafluoro-ethylene electromagnetic field, min in combination with colloidal nickel 2 5 1. Tensile strength, kg/cm 133 l 12 96 2. Ultimate elongation, percent 132 57 50 3. Brinell hardness, kglmm' 4.23 3.4 2.23 4. Colloidal nickel content,

percent 0.03 0.09 0.15

EXAMPLE 7 TABLE 8 Physico-mechanical properties Duration of treatment, sec

of polytetrafluoro-ethylene with 10 percent aluminum content 30 60 1. Tensile strength, kglcm 108 1 l4 2. Ultimate elongation, percent 57 48 It should be pointed out that due to polytetrafluoroethylene having fibrous structure and being readily liable to get lumpy when exposed to cold, it is impossible to obtain a uniform mixture with a 10 percent of powdered aluminum content when employing padd1e-, drum-, vibration-type mixers and those of the colloidmill type on account of the material becoming exfoliated when caked. By using the method in contemplation it is possible to obtain a material with the aluminum content even in excess of 10 percent.

EXAMPLE 8 A mixture comprising 180 g of polytetrafiuoroethylene and g of powdered nickel, is placed within the active zone of rotating electromagnetic field in the TABLE 9 Duration of treatment in electromagnetic field, sec

Physico-mechanical properties of polytetrafluoro-ethylene with a 10-weight percent content of 30 60 powdered nickel 1. Tensile strength, kg/cm 147 2. Ultimate elongation, percent 202 3. Brinell hardness, kg/mm 4.71 4.41 4. Aluminum content, percent 10 10 EXAMPLE 9 A mixture composed of 14 g of pulverbakelite (finely divided mixture of novolac phenol-formaldehyde resin with 7.4 percent of urotropine), 126 g of powdered aluminum and steel particles (dia. 0.7 mm and 67 mm long), is placed in rotating electromagnetic field within 1 minute, the adequateness of spreading the components in the mixture being determined by way of chemical analysis of the samples taken from different parts of the mixture.

The results of determining the adequateness of the component intermixing are tabulated in Table 10 below. Herein are also quoted (for the cake of comparison) the results of determining the adequateness of intermixing the components in a plant of the rotating drum type during 5 hrs.

A mixture containing g of polytetrafluoroethylene, 20 g of powdered nickel and 300 ml of ethyl alcohol is introduced for different periods of time into the active zone of rotating electromagnetic field in the presence of ferromagnetic particles protected with polytetrafluoro-ethylene coating.

Then the solid phase is isolated through the filtering under a vacuum-pump, the preparation technique of a composition from polytetrafluoro-ethylene with a 10 percent nickel content is similar to that described with reference to Example 1.

Data on the'influence of the mixing conditions upon the physico-mechanical properties of the metalpolymer composition obtained are found in Table 11 below.

TABLE 11 Physico-mechanical properties of polytetrafluoro-ethylene with a lO-percent nickel content when Duration of mixing in electromagnetic field, sec

mixing in the ethyl alcohol 30 60 medium 1. Tensile strength, kglcm 156 146 2. Ultimate elongation, percent 152 145 3. Brinell hardness, kglmm 5.14 5.14

romagnetic particles are coated with a protective polymeric film.

5. A method as claimed in claim 4, wherein the ferromagnetic particles are coated with a protective polytetrafluoro-ethylene film.

6. A method as claimed in claim 3, wherein use is made of unequiaxed ferromagnetic particles.

7. A method as claimed in claim 6, wherein use is made of cylindrical-shaped ferromagnetic particles.

8. A method as claimed in claim 1, wherein said polymer medium is in liquid state (liquid polymer).

9. A method as claimed in claim 1, wherein said polymer medium is in solid powderlike state.

10. A method as claimed in claim 1, wherein polytetrafluoro-ethylene is employed as a polymer medium.

1 l. A method as claimed in claim 1, wherein epoxide resin is employed as a polymer medium.

12. A method as claimed in claim 1, wherein no Volac phenol-formaldehyde resin is employed as a polymer medium.

13. A method as claimed in claim 1, wherein polyamide is employed as a polymer medium.

14. A method as claimed in claim 1, wherein the particles of ferromagnetic metals are employed as ferromagnetic particles.

15. A method as claimed in claim 1, wherein the particles of ferromagnetic metal alloys are employed as ferromagnetic particles. 

2. A method as claimed in claim 1, wherein the metal component is ferromagnetic particles.
 3. A method as claimed in claim 1 wherein said metal component is a mixture of ferromagnetic and non-Ferromagnetic metal particles.
 4. A method as claimed in claim 3, wherein the ferromagnetic particles are coated with a protective polymeric film.
 5. A method as claimed in claim 4, wherein the ferromagnetic particles are coated with a protective polytetrafluoro-ethylene film.
 6. A method as claimed in claim 3, wherein use is made of unequiaxed ferromagnetic particles.
 7. A method as claimed in claim 6, wherein use is made of cylindrical-shaped ferromagnetic particles.
 8. A method as claimed in claim 1, wherein said polymer medium is in liquid state (liquid polymer).
 9. A method as claimed in claim 1, wherein said polymer medium is in solid powderlike state.
 10. A method as claimed in claim 1, wherein polytetrafluoro-ethylene is employed as a polymer medium.
 11. A method as claimed in claim 1, wherein epoxide resin is employed as a polymer medium.
 12. A method as claimed in claim 1, wherein no Volac phenol-formaldehyde resin is employed as a polymer medium.
 13. A method as claimed in claim 1, wherein polyamide is employed as a polymer medium.
 14. A method as claimed in claim 1, wherein the particles of ferromagnetic metals are employed as ferromagnetic particles.
 15. A method as claimed in claim 1, wherein the particles of ferromagnetic metal alloys are employed as ferromagnetic particles. 